Pulmonary Emboli and Pulmonary Infarction

Question 1

Pathogenesis of pulmonary emboli

Answer 1

Peripheral venous thrombus becomes a thromboembolus that travels up ivc and through the right heart to lodge within and occlude a pulmonary artery branch
Thrombi, usually in the deep leg veins of lower extremities (>95%) or pelvis and right atrium,

Question 2

What does rarely pulmonary emboli consists of?

Answer 2

Fat, air, bone marrow (From fractures) or tumour

Question 3

Clinical significance of the embolus depends on?

Answer 3

Extent of pulmonary artery occlusion
Cardovascular health of the patients

Question 4

Emboli can causes what?

Answer 4

respiratory compromise(due to nonperfusion of a ventilated segment i.e.ventilation-perfusion mismatch)
hemodynamic compromise (due to increased resistance to pulmonary blood flow) can cause
sudden death or
acute cor pulmonale (right heart failure)

Question 5

At risk the pulmonary emboli forms what?

Answer 5

Primary or secondary hypercoagulable states

Question 6

List the 2 clinical findings and explain them of the pulmonary emboli

Answer 6

Large pulmonary emboli
Sudden death
If the atient survives, symptoms mimic mycoardial infarction
Smaller emboli may be
Asymptomatic or
Dyspnoea, mild transient chest pain, pleuritic pain, cough.

Question 7

List clinical course of pulmonary emboli

Answer 7

Smaller emboli often resolve via contraction and fibrinolysis;
Multiple small emboli may lead to pulmonary hypertension and cor pulmonale.
Risk of recurrence, especially in patients with underlying risk factors.

Question 8

Thromboembolus displays what?In the gross appearance

Answer 8

Display an Irregular surface, pale tan areas admixed with dark red areas

Question 9

Embolus has an outline of the veins in which it originally formed as a ?

Answer 9

thrombus

Question 10

Large emboli lodge in which artery and does what?

Answer 10

Large emboli lodge in the main pulmonary artery, its branches /at the bifurcation (‘saddle Embolus’).

Question 11

Smaller emboli travel where and can cause what?

Answer 11

Smaller emboli travel more distally (usually lower lung lobes) and can cause a wedge- shaped area of haemorrhage or infarction

Question 12

Infarct are common if the patients cardiovascular function is?

Answer 12

Poor and the bronchial artery supply is insufficient to sustain the lung parenchyma

Question 13

Explain what is meant by lung infarcts

Answer 13

Haemorrhagic, with the pleural surface covered by a fibrinous exudate.
Within 48h, the infarct becomes paler and red-brown as the red blood cells lyse and haemosiderin is produced.
Eventually, the infarct is replaced by fibrous tissue and forms a scar

Question 14

What distinguish between pulmonary embolus from a postmortem blood clots

Answer 14

Line of Zahn

Question 15

The area of infarct shows what?

Answer 15

Ischaemic necrosis of alveolar walls, bronchioles and vessels

Question 16

The pulmonay infarct gross appearance?

Answer 16

Medium-sized thromboemboli (blocking a pulmonary artery to a lobule or set of lobules) can produce a hemorrhagic pulmonary infarction (←) because the patient survives

Question 17

Explain how the infarct look?

Answer 17

The infarct is wedge-shaped and based on the pleura.
These infarcts become hemorrhagic because, although the pulmonary artery carrying most of the blood is cut off, the bronchial arteries from systemic circulation (supplying 1% of pulmonary blood to lung interstitium) are not cut off.